RESEARCH OBJECTIVES: The research of Epstein's laboratory is concerned with three aspects of the neuropsychology in ingestive behavior: 1) the physiological mechanisms of thirst, 2) the chemical controls of food intake, and 3) the ontogeny of ingestive behavior. Studies of the physiological mechanisms of thirst will emphasize the role of angiotensin in the mobilization of the thirst of extracellular depletions. The means by which it enters the brain and affects sensitive tissue will be sought and its interactions with the osmosensors for thirst that are focussed in the lateral preoptic area will be studied. Two approaches will be taken to the study of the chemical controls of food intake. First, denervation procedures are being employed to describe the mechanism of cholecystokinin-induced food satiety, with particular attention to the hepatic branches of the vagus. Second, physioligical doses of catecholamines will be used to analyze the possibe adrenergic mechanism for the arousal and suppression of the brain mechanisms for meal taking. The ontogeny of feeding and drinking will be studied in suckling and weanling rats with both appetitive and reflexive testing. The chronology of development of the separate physiological controls of each mode of ingestive behavior will be described and their assembly into adult feeding and drinking analyzed.